Operating heads for insulation strippers



Nov. 9, 1965 D. s. STALLINGS 3,216,110

OPERATING HEADS FOR INSULATION STRIPPERS Filed June 14, 1963 2 Sheets-Sheet l INVENTOI- Jazqyhs 5. 65a 272757;

ATTORNEY Nov. 9, 1965 D. s. STALLINGS 3,216,110

OPERATING HEADS FOR INSULATION STRIPPERS Filed June 14, 1963 2 Sheets-Sheet 2 INVENTOR JawyZzi ,5: 'ialla'lga ATTORNEY United States Patent 3,216,110 OPERATING HEADS FOR INSULATION STRIPPERS Douglas S. Stallings, 353 Best Gate Road, Annapolis, Md. Filed June 14, 1963, Ser. No. 287,933 6 Claims. (Cl. 91)

This invention relates to operating heads in combination with insulation stripping tools of the type particularly disclosed in applications Ser. No. 266,438, filed March 19, 1963, and Ser. No. 287,932, filed concurrently herewith, in which the tools are swung about the cable for circumferential cuts through the insulation sheating, and drawn lengthwise of the cable for longitudinal cuts together with depth of penetration limiting means provided to avoid cutting or nicking the metallic conductors encased in the sheathing.

In operating on overhead conductors it is sometimes difficult to draw the tool along the cable for the longitudinal cuts, so the primary object of the present invention is to facilitate such operations and to provide a cutting element with means whereby damage to the metallic conductor is positively prevented.

Accordingly, I have provided a cutting assembly in the form of an auxiliary head which is interchangeable with the cutter assemblies of said earlier patent applications, my new auxiliary head embodying a rotary disk type cutter with cable insulation gripping elements associated therewith and a driver which when rotated by the lineman operator efiects a positive movement of the tool for longitudinal cuts into the sheathing and with greater case than heretofore. While this auxiliary head does not interfere with making of circumferential cuts in the sheathing in the manner set forth in said earlier applications for larger cable such cuts are facilitated.

To prevent engagement of the cutting disk with the metallic conductor when making a cut through the insulation the disk cutter is flanked by cylindrical disks of such a diameter that the blade projects beyond slightly less than the thickness of the insulation sheathing on the cable so that when these blade flanking disks engage the sheathing the blade cannot cut through the sheathing sufficiently to ever come into engagement with the metallic conductor.

A further object of this invention is to provide a cutting disk and associated gripping elements which will penetrate the sheathinghigh density poly-ethyl plastic or other hard types of insulation and even lead sheathing-with ease and without much strain on the stripping tool. Accordingly, as few gripping elements as possible are employed, preferably in the form of sharp pointed teeth projecting from the blade flanking disks in a staggered relationship so that one tooth at a time fully penetrates the sheathing, first on one side then the other of the blade and the sheathing will be as free as possible of sidewise engagement of the teeth therewith, particularly when the tool is being positioned on the cable for an insulation cutting operation.

While this auxiliary head is similar in many respects to the cutting assembly heads disclosed in the earlier applications, the adjustable depth of cut limiting member disclosed in said applications is not essential where the cutting disk is flanked by the depth of cut cylindrical disks and projecting beyond the cutter disk support the depth of penetration remains the same throughout the range of the tool; the thickness of the insulation sheathing of different sizes of cables is the same where the same operating conditions prevail throughout the power system. However, where cables having a different thickness of insulation sheathing is employed a cutting disk with the appropriate sized cylindrical rings may be quickly substituted in the supporting head.

It is also an object of this invention to provide blades which have lateral contours formed in their side surfaces as close to their cutting edges as practical which operates as traction elements for moving the blade to produce the cut in the sheathing.

It the following specification other objects and advantages will appear in describing a preferred practical embodiment of my invention and modifications illustrated in the accompanying drawings wherein the auxiliary head is shown applied to the tool shown in said application Ser. No. 287,932 in which organization many adventages and benefits are derived as will appear hereinafter.

In the drawings:

FIG. 1 is a side elevation of a stripping tool to which the auxiliary head is applied with a cable in position for a circumferential out, parts of the structure being broken away to show the clamping mechanism.

FIG. 2 is an end view thereof on a slightly larger scale with parts broken away to show a complete side elevation of the auxiliary head, with a cable in position for a longitudinal cut in its sheathing.

FIG. 3 is an exploded view of the parts of the auxiliary head.

FIG. 4 is an edge elevation of the assembled disk cutter and its flanking disks.

FIG. 5 is a side elevation thereof.

FIG. 6 is a schematic side elevation of one of the flanking disks.

FIG. 7 illustrates portion of a cable with circumferential and longitudinal cuts in the sheathing made by the auxiliary head.

FIG. 8 is a fragmentary side elevation of a modified operating head to support a different cutter disk.

FIG. 9 is a side view of a cutter blade with knurled surfaces on the sides thereof.

FIG. 10 is a similar side View of a'cutter blade having a series of apertures therethrough adjacent to the cutting edge and formed with depth of cut limiting flanking cylinders.

FIG. 11 is an edge elevation thereof.

Since the auxiliary head in accordance with my invention operates more efficiently in conjunction with a stripping tool provided with clamping means for continuously holding the cutter in a definite position in the cable sheathing during a cutting operation and other cooperating features I have shown it applied as the cutting assembly 13 to the tool covered in said application Ser. No. 287,932, the essential parts of the tool and cooperation of the auxiliary head therewith being shown in FIGS. 1 and 2.

The stripping tool includes upper and lower hand lever elements 10 and 11 respectively pivotally connected at 12 and carrying cutter and cable supporting assemblies 13 and 14. These assemblies cooperate for cutting the sheathing 15 on a conductor cable 16 which, as shown in FIG. 1, is positioned for a circumferential cut into the sheathing 15 and in FIG. 2, a longitudinal cut. A flat type spring element 17 mounted in upper handle lever 10 and associated with an adjustable clamping element link 43, operates to yieldingly urge the levers 10 and 11 to an open position. Handles 10 and 11 are provided with gripping elements 18 adjacent to the cutter and supporting assemblies for the stripping of the cut portions of the cable insulation.

The cable supporting assembly 14 includes a channel support member, or bucket 35 formed to extend laterally from lower lever 11 and has a pair of grooved rollers 36 mounted on pivots 37 extending through the sides of the channel member 35 and both sides 11a and 11b of lever 11.

The clamping element link 43 consisting of a relatively thick plate is pivoted at 44 to lower lever 11 below its pivotal connection 12 with upper lever and extends upwardly beyond pivot 12. The upper portion of link 43 is provided with a slot 45 through which an abutment pin 46 secured in upper lever 10 extends, and is engageable by the side walls and an end of the slot. This Plate has an extension portion 38 engageable with the end of spring 17 which in turn urges the side wall 39 of the slot into engagement with the pin to yieldingly swing the levers 10 and 11 to their open position. These parts function to limit the extreme opening and closing positions of the levers and also for variable adjustment of the closing of the levers 10 and 11 with respect to sizes of cables being operated upon by the cutting element, that is the grip thereon. For this adjustment clamping element 43 has its lower end portion 50 extending downwardly below its pivotal connection at 44 with lower lever 11 and is engaged by an element such as a cam for rocking or holding the link 43 on its pivot; this cam element is preferably in the form of a screw 51 extending through the lower portion of the channel lever 11 through a threaded element 52 therein between roller pivots 37 and there beyond is guided in a crimped portion in lever handle 11. Screw 51 terminates beyond the end of lever 11 in a relatively large operating head 54 by which the adjustment of the opening of the levers is achieved. A very slight play of abutment pin 46 between the side walls of slot 45 and the cooperation of spring 17 with clamping link 43 provided for a slight back-off of the cutter during an initial cut and spring loaded cuts thereafter as more fully described in the aforesaid application.

The cutter assembly 13 in accordance with the invention consists of an interchangeable operating head for such stripper tools as above described. It includes a cutter support 201 extending laterally from lever 10 detachably secured by means of a reduced cylindrical portion 21 thereof providing a connecting element extending through corresponding apertures in both side portions of handle lever 10 with a spacing sleeve 211 thereon between the side portions and secured in place by means of a nut 23 on the threaded end thereof. Support 201 is provided with a slot 241 in its lower side portion for receiving a disk cutter 251 and flanking cylindrical disks 252 at each side thereof which are mounted on the inner end of a drive shaft extending into the end of the support.

In common with other operating heads for stripping tools the cutter support 201 is aflixed to the handle with the proper angular position. Thus, as viewed in FIG. 1, the cutter support 201 is tilted to a slight extent downwardly to the left. To provide for this all the operating heads are provided with positioning elements such as shown at 212 for insuring proper engagement in the stripper lever.

The cooperation of this traction cutter head with a stripping tool having the desired operating functions is shown in FIGS. 1 and 2 wherein the head is shown in end and side elevation. FIGS. 3 to 6 are details thereof.

Cutting disk 251 and flanking cylindrical disks 252, between which the cutting disk is sandwiched, are provided with central apertures having a close fit over a square sleeve 253 on which they are mounted and thereafter the ends of the sleeve are peened to secure the parts as an integral unit. Sleeve 253 has a sliding fit on a squared portion 262 of drive shaft 261 whereby the unit may be turned by the rotation of shaft 261.

Shaft 261 has inner and outer cylindrical bearing portions 263 and 264 for engagement with corresponding bores in support 201, and a groove 265 in the shaft is engaged by the lower bifurcated end of a retainer plate 202 secured to cylindrical support 201 by means of a screw 203.. Thus if for any reason it is desired to change the cutter assembly unit removal of screw allows shaft 261 to be'withdrawn from the parts. A handle 266 has a pivotal connection 267 with the outer end of drive shaft 261 and a spring pressed detent 268 yieldingly holds it straight out from the shaft, as shown in FIG. 1 while making a circumferential cut, if desired, or allows it to be swung outwardly in a position for rotating the shaft for making longitudinal cuts as shown in FIG. 2.

Referring again to the cutting and flanking disks assembly unit, particularly FIGS. 4 and 5, it is pointed out that sole purpose of the cylindrical surfaces of the two flanking disks 252 is to provide a rolling contact engagement with the surface of the conductor insulating sheathing and thereby limit the penetration of the blade of cutting disk 251 to a uniform distance therebeyond, slightly less than the thickness of the sheathing of the different sized cables. For conductor cables now in use we have found this distance inch projection of the blade beyond the cylindrical surfaces of the flanking disks to be satisfactory; even though the insulation is not completely severed the small amount uncut breaks away in the stripping. Even for softer forms of insulation which may yield under pressure of the disks there is suflicient leeway so that the metallic conductors encased therein will not be damaged or contacted by the cutter blade.

For traction of the flanking disk with respect to the cable sheathing the cylindrical surfaces of each of them are formed with four sharp pointed integral teeth 254, degrees apart, projecting from the cylindrical surface sufliciently to penetrate quite deep into the sheathing. The eight teeth are 45 degrees apart in staggered relationship on opposite sides of cutting disk 251. FIG. 7 illustrates a cable with circumferential and longitudinal cuts therein and shows the pattern formed by the gripping or traction teeth. 254. The staggered relationship of these teeth is shown in FIG. 4 and represented in FIG. 5 by the four dark teeth on the face side and the four light teeth which are behind blade 251; by this arrangement there will be at least one tooth penetrating the sheathing at all times and very little pressure is required to place the tool into cutting position on a cable, due to the absence of teeth which would exert side pressures against the surface of the sheathing.

The two flanking disks 252 on opposite sides of cutting disk 251 are identically the same. To accomplish this reference to the schematic view, FIG. 6, wherein the disk, and its square opening symmetrically, are centered with respect to X and Y axes, and the four dark traction points 254 are each 22 /2 degrees in advance of the axes in a clockwise direction. The outer face of the disk is inscribed OUT, meaning: away from the face of the cutter disk. When the disk is turned over for engagement with the other side of the cutter as denoted by the light teeth 254, they are in 22 /2 degrees retarded position with respect to the axes. The disks can be similarly constructed for a key drive, but the square shank drive is preferred.

By referring to FIG. 4 it will be noted that each of these flanking disks is formed laminated, preferably three layers at least of spring steel which may be readily stamped and suitably united; this affords lower manufacturing costs and a tougher flanking disk.

I have described above the preferred form of my invention (which I elect in advance, if essential), however in FIGS. 8 to 11 I illustrate modifications wherein the cutter disks are formed traction means for engagement with the sides of the cuts in the sheating.

In these forms the cutter assembly 13 consists of an interchangeable operating head the same as in the preferred form of the invention except the cylindrical support 204 has a narrower slot 242 for accommodating the disk type cutters 255 and 257 shown in FIGS. 9 and 10. The drive shaft 261 and handle 266 are the same, likewise their operation in rotating the cutters. In all forms of the invention it is essential the cutting blade should be vertical and in the central longitudinal plane with respect to the supporting rollers for longitudinal cuts.

In FIG. 9 the disk cutter 255 is shown provided with knurled side surfaces 256 swirling inward in a clockwise direction from points a little inward of the edge of the blade on the side of the blade in view, and in a counter clock-wise direction facing the reverse side, so in effect they are in the same direction; they have good traction with the sides of the cut in the sheathing when the blade is rotated in the cut in a counter clockwise direction for the initial cut but substantially less when turned clockwise for this cut. Since the disk is relatively thick as compared with the thin disk cutters in making cuts the insulation is pressed outward and tends to spring back into engagement with the serrations provided by the knurling thereby providing the traction.

While cutter disk 255 has no depth of penetration adjusting or controlling means satisfactory longitudinal cuts have been made with it. While an adjustable depth of cut member such as shown in the earlier applications may be employed with it, the experienced operator can set the blade to cut the proper depth by the feel of the tool, particularly when the stripper, as shown in the drawings, has the back off and spring loaded cutting features.

In FIGS. 10 and 11 the cutter disk 257 has a thinner cutting edge formed with a series of apertures 258 for traction with the sides of the cuts as close to the cutting edge as practical and with unitary cylindrical flanking side members 259 with the cylindrical surfaces knurled for traction with the outer surface 'of the sheathing and this also limits the depth of penetration of the cutting blade.

Cutter disk 255 is an example of lateral traction contours. Disk 255 being thicker requires a greater pressure by the tool levers but it has numerous advantages which are readily apparent.

Disk 257 has the advantages aflorded by a thinner blade and depth of cut limiting means.

In the foregoing specification I have set forth embodiments of traction heads for both circumferential cuts and longitudinal outs in cable sheathing. These embody traction means on or associated with the sides of the cutting blades on the sides of the blade, on both the sides of the blade and cylindrical flanking disk elements, and on the cylindrical surfaces of flanking disks alone. Also, operating heads which are provided with drive shafts for rotating cutting disk type blades although they may be otherwise employed or modified for other types of cutters or operating tools.

Having described the preferred form and modifications of the cutting head in detail various changes may be made Within the scope of my invention as defined in the following claims.

I claim:

1. A cutting unit comprising, a cutting disk, a pair of cylindrical disks flanking said cutting disk and beyond which the cutting edge of the cutting disk projects, spaced apart traction teeth projecting outward from the cylindrical surfaces of said flanking disks so that one tooth at a time on alternate sides of the cutting disk will be in a penetrating position in material being cut by the cutting disk and a minimum number of teeth 'on either side thereof will ever be in engagement with the material being cut, and means for securing said cutting and flanking disks together as a unit and for providing a driving connection between a rotatable shaft and the cutting unit upon which it is mounted.

2. A cutting unit comprising, a cutting disk, a pair of cylindrical disks flanking said cutting disk and beyond which the cutting edge of the cutting disk projects, four traction teeth projecting outward from the cylindrical surfaces of said flanking disks degrees apart around the cylindrical surfaces thereof, and means for securing said cutting and flanking disks together as a unit with the traction teeth of one flanking disk 45 degrees apart with respect to the traction teeth on the other flanking disk.

3. A tool head and cutter for an electrical cable sheathing stripper, said stripper including a pair of lever members pivotally connected at one end, one lever member having a laterally extending cable support and the other lever member having a transverse opening therethrough in a position to receive :a tool head for extending laterally above the cable support, said tool head having an end portion extendable through said lever opening and having a detachably securable connection with the lever, said tool head having an outer end portion with a transverse slot extending upwardly from its lower surface, a drive shaft extending through the outer end of said tool head and across said slot, and a circular cutting element having flanking depth-of-cut cylinders with outwardly projecting traction teeth thereon mounted on said drive shaft in said slot so as to project downwardly therefrom toward said cable support when said tool head has been extended through said lever opening.

4. A cutter operating head for a stripper tool having a cylindrical opening therethrough adapted for receiving the operating head comprising, a longitudinally and normally horizontally extending cutter support, means for rotatably mounting a disk type cutting blade thereon so as to project from the support downwardly from the lower side thereof adjacent to its outer end, a cylindrical connecting element extending from the other end of said support for mounting the head in said opening, key means on the connecting element to cooperate with the stripper tool for determining the angular relationship of the head when mounted thereon, and means for releasably securing the head in position.

5. An interchangeable operating head for stripper tools and the like having a cylindrical opening therethrough for receiving one end of the operating head, said operating head including a longitudinally and normally horizontally extending support with an upwardly extending recess therein adjacent to its other end for receiving a cutter, means for detachably connecting the said one end of the support to the tool, a disk type cutter in said support recess projecting downwardly therefrom, and a rotatable drive shaft extending through the other end of said support and into said recess therein, means mounting said blade on said shaft so as to be turned therewith and means connected to said shaft for rotating it.

6. A cutter head assembly adapted for use in a cable stripper, said cable stripper including a pair of lever members pivotally connected at one end thereof, one of said lever members having a laterally extending cable support and the other of said lever members having a transverse opening adapted to receive said cutter head assembly in a position above said cable support, said cutter head assembly comprising a threaded shank end portion adapted to extend through said opening and having means thereon for holding said head assembly at a predetermined angular position relative to said other of said lever members when mounted therein, a nut on said shank end portion detachably securing said cutter head assembly when mounted on said other of said lever members, an enlarged head connected to said shank end portion, a transverse slot in said enlarged head extending upwardly from a lower surface thereof, a circular cutting element pivotally mounted on said enlarged head in said slot on an axis spaced downwardly from the axis of said shank end portion, said cutting element thereby projecting downwardly toward said cable support when mounted.

(References on following page) 7 References Cited by the Examiner 2,317,944 UNITED STATES PATENTS 2,647,309 2,716,280 608,919 8/98 Sell. 653,137 7/00 Feiten. 5 660,829 10/00 Angell 30-347 X 661,022 866,356 9/07 Haas 30 104 225 280 1,077,951 11/13 Beck 30-102 1,833,980 12/31 Thewes 30-102 1,841,251 1/32 Miller.

'8 4/43 Schaefer. 8/53 Chisena. 8/55 Ruhe 30101 X FOREIGN PATENTS 6/3 8 Germany. 6/24 Great Britain.

WILLIAM FELDMAN, Primary Examiner. 

1. A CUTTING UNIT COMPRISING, A CUTTING DISK, A PAIR OF CYLINDRICAL DISKS FLANKING SAID CUTTING DISK AND BEYOND WHICH THE CUTTING EDGE OF THE CUTTING DISK PROJECTS, SPACED APART TRACTION TEETH PROJECTING OUTWARD FROM THE CYLINDRICAL SURFACES OF SAID FLANKING DISKS SO THAT ONE TOOTH AT A TIME ON ALTERNATE SIDES OF THE CUTTING DISK WILL BE IN A PENETRATING POSITION IN MATERIAL BEING CUT BY THE CUTTING DISK AND MINIMUM NUMBER OF TEETH ON EITHER SIDE THEREOF WILL EVER BE IN ENGAGEMENT WITH THE MATERIAL BEING CUT, AND MEANS FOR SECURING SAID CUTTING AND FLANKING DISKS TOGETHER AS A UNIT AND FOR PROVIDING A DRIVING CONNECTION BETWEEN A ROTATABLE SHAFT AND THE CUTTING UNIT UPON WHICH IT IS MOUNTED. 